A letter from Rose Fitzgerald Kennedy’s caused consternation in the Kremlin – at the height of the Cold War and Cuban missile crisis.

A summer school at the Kennedy ancestral home in Wexford has heard how JFK’s mother sparked a major investigation in Moscow.

Her grandson Ted Kennedy Jnr, in Wexford to address the Kennedy Summer School in New Ross, recalled how his grandmother was fond of giving signed books as Christmas presents.

Ted recalled how his grandmother’s habit led to a major Soviet investigation at the height of the Cold War.

The Irish Times reports that a letter from Rose arrived on the desk of Soviet secretary general Nikita Khrushchev as he was penning a personal letter to President Kennedy about the Cuban missile crisis..

He explained: “She liked to give presents of signed books so if somebody published a book she would get the author to sign a few copies and give them as Christmas presents.

“And so it was that at the very height of the Cuban missile crisis when Soviet secretary general Nikita Khrushchev was penning a personal letter to President Kennedy that a letter arrived on his desk from “a Rose Kennedy of Hyannis Port, Massachusetts, asking him to sign some of his books.

“The KGB were very interested in the letter and had hundreds of people analysing it, trying to figure out what message the Kennedys could be sending.”

The New Ross audience laughed as Kennedy confirmed the CIA also took an interest in the letter.

He added: “As nuclear warfare was about to break out the CIA also became aware to the communication and so too her son, President John F Kennedy.

“When the president remonstrated with his mother, Rose said it was a simple matter

“Every year she picked an author, and this year it was Mr Khrushchev’s turn.”

Kennedy Jnr recalled how the President patiently explained that while the CIA accepted it was a simple, unrelated issue, that agency would then have to employ ‘hundreds of people’ to figure out what the soviets might have thought the letter meant.